Attention has been given in recent years to “circular agricultural cycle” in which cultivated agricultural crops again return as compost to agricultural lands, and various efforts are made everywhere. The reason why the “circular agricultural cycle” has received attention is that it is expected as an effective means of: improving fertilizer self-sufficiency by effective use of waste; or increasing soil fertility reduced due to the heavy use of chemical fertilizers by using compost.
In Japan, agriculture using chemical fertilizers providing necessary nutrition to soil has conventionally been carried out as a very efficient and effective method for increasing the yield of agricultural crops. Thus, salt damage by agricultural chemicals supplied in excess, problems with ammonium sulfate spread for supplying nitrogen, and the like have become pointed out in recent years.
The “circular agricultural cycle” as a substitute for the use of chemical fertilizers requires composting animal and plant waste with microorganisms. Known methods for such composting of waste include, for example, the following techniques.
Japanese Patent No. 3378858 describes a method for treating an organic waste being capable of converting organic waste to a useful organic fertilizer by using a carbonaceous base material, such as sawdust, straw, rice husks, twigs, bark, wood chips, bark, or duct, and activated mixed microorganisms having the action of fermenting and decomposing organic matter. As the microorganisms, mold, yeast, and the like are also described in addition to bacteria, such as Bacillus subtilis and Bacillus stearothermophilus. 
Japanese Patent No. 3406100 describes a method for producing an organic fertilizer comprising adding an actinomycete of the genus Streptomyces, a bacterium of the genus Pseudomonas and/or a bacterium of the genus Bacillus to organic matter containing 20% by weight or more of arabinoxylan, and then fermenting the organic matter with such microorganism.
Japanese Patent Publication (Kokai) No. 2002-293681 A describes a method for producing a bark-like compost, comprising adding a nitrogen source, such as chicken dropping or urea, to the cortex of trees, such as broadleaf and needle leaf trees, and then adding thereto an aerobic ultra-thermophilic bacterium, such as an bacterium of the genus Bacillus, and then fermenting and maturating the cortex of trees with the aerobic ultra-thermophilic bacterium.
Japanese Patent No. 3789303 describes a method for fermentation treatment comprising adding Bacillus subtilis takemi strain to organic waste, a method using bacteria for reducing bitterness, and the like.
Japanese Patent Publication (Kokai) No. 2013-060378 A describes a method for composting organic waste or litter, comprising killing harmful microorganisms and, at the same time, composting the organic waste by mixing at least one microorganism selected from the group consisting of the genera Bacillus, Geobacillus, and Aeribacillus in the organic waste or litter.
Japanese Patent Publication (Sai-kohyo) No. 2004-067197 A describes a method for treating organic waste characterized by allowing a mesophilic bacterium having activity at 15-50° C. (Bacillus subtilis) and a thermophilic bacterium having activity at 50-70° C. (Bacillus pallidus) to exsit in the organic waste.
The following things are specifically disclosed as problems with techniques using chemical fertilizers.
The drawbacks of heavy usage, such as soil pollution and death of soil bacteria, have come to the surface due to use of chemical fertilizers having been useful for yield expansion (Japanese Patent Publication (Kokai) No. 2007-210857).
The heavy usage of agricultural chemicals/chemical fertilizers causes continuous cropping hazard for which the root hair is discolored to make phosphorus and minerals unabsorbable, and also results in the death of effective soil microorganisms and the inhibition of the food chain between effective microorganisms and plants (Japanese Patent No. 3789303).
Meanwhile, problems with the “circular agricultural cycle” include the problem of effort required and challenges such as the stabilization of the quality of compost. For example, unlike the composting of animal waste, such as livestock manure, and the like, techniques more specialized for plant waste utilization is required for plant waste and domestic garbage. Specifically, although cereal waste, such as wheat bran and defatted rice bran, has conventionally been known to be effective as a raw material for an organic fertilizer, it takes a long time (typically, about 40 days to 2 months) to compost because of being rich in cellulose and hemicellulose, which are less easily decomposed (Japanese Patent No. 3406100).
The solution of the above problems is needed to realize the circular agricultural cycle, and the supply of a good-quality and completely matured compost from organic waste as a biomass resource to agricultural producers will enable the production of good-quality agricultural products in high yield and will also realize the so-called circular agricultural cycle in which compost is produced from the waste and used for the production of agricultural products.
An object of the present invention is to provide a method for producing a good-quality compost from organic waste as a biomass resource for realizing the circular agricultural cycle, and the compost.
Another object of the present invention is to provide a method for producing taste-improved vegetables using the compost.